The role of the mesangial cell in proliferative glomerulonephritis

In 40 patients with a histological diagnosis of proliferative glomerulonephritis the deposition of immunoglobulins, complement (C(3)), and fibrin/fibrinogen has been assessed by immunofluorescence and electron microscopy. The results of such examinations have been correlated with the outcome of the illness. In minor or resolving disease there is usually minor functional impairment, a good response to therapy or spontaneous resolution, the deposition of small amounts of material in glomerular capillary walls, and active mesangial removal. In moderate to marked disease there is initially a moderately severe functional disorder, a good response to therapy, considerable deposition of material in glomerular capillary walls but with less active mesangial regions than in the previous group. In progressive glomerulonephritis there was initial severe functional disorder, poor response to therapy, large amounts of material deposited within capillary walls, and active mesangial regions which were greatly enlarged, containing numerous deposits. In the rapidly progressive group there was severe functional disorder with poor response to therapy, the deposition of only small amounts of material within capillary walls, the lack of any significant mesangial cell reaction, and the formation of epithelial crescents. The results of the study indicate that in proliferative glomerulonephritis following the deposition of material in glomerular capillary loops, the progression of the disease is, to some extent at least, dependent upon the ability of the mesangial cell to remove such material.

Identification of intrarenal fibrin deposition

The site and extent of intrarenal fibrin deposition has been examined by routine histological staining, immunofluorescence, and electron microscopy in 109 patients with a wide variety of renal diseases. The findings have been correlated with the amount of urinary fibrin/fibrinogen degradation product (FDP) excretion as measured by the tanned red cell haemagglutination inhibition immunoassay. The results show that routine histological stains (Martius Scarlet Blue and Picro Mallory) are unreliable, particularly where there is mesangial accumulation of material or where the amount of fibrin deposited is small and confined to a subendothelial position. Similarly the electron microscope may overassess the degree of fibrin deposition, particularly if this is associated with the deposition of immunoglobulins and complement. There is a close relationship between the site and extent of fibrin, as detected by immunofluorescence, and the maximal urinary FDP excretion.

Thrombotic microangiopathy in rheumatoid arthritis

The syndrome of thrombotic microangiopathy is described in an elderly woman with active rheumatoid arthritis and thyroiditis. Phenylbutazone and imipramine were used in treatment immediately before thrombocytopenia was recognised and the possible role of these drugs in precipitating microvascular thrombi in rheumatoid arthritis is discussed.

Mass immunization in the control of infectious disease

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Treatment of Mustard Gas Burns

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